JSFiddle - React, Tailwind, and code Playground

HTML

<script>
    window.onload = function() { 
      check_book();
    }
    function check_book(){
    var book = document.getElementsByName('hotel');
      for (i=0; i < book.length; i++) {
            if (book[i].checked == true) {
              if (book[i].value == 'no'){
                document.getElementsByName('hotel_pref')[0].disabled=true;
                document.getElementsByName('hotel_BLA')[0].disabled=true; 
              }
              else {
                document.getElementsByName('hotel_pref')[0].disabled=false;
                document.getElementsByName('hotel_BLA')[0].disabled=false; 
              }
              break; 
            }
      }
    }
</script>    
    
<body>
<br>
<form action="send_form_email.php" method="post" name="contactform">
    <table border="0" width="500">
       
<tr>
         <td valign="top"><label for="hotel"><font face="verdana" size="2">Do you want to book your hotel
            through our agent?</font></label> </td>
            <td valign="top">
<input type="radio" name="hotel" value="yes" onclick="check_book();" checked="true">Yes<br>
<input type="radio" name="hotel" value="no" onclick="check_book();">No<br>
            </td>
        </tr>
        <tr>
            <td valign="top"><label for="hotel_pref"><font face="verdana" size="2">Hotel preference</font></label> <select
            name="hotel_pref" size="1">
                <option value="Dorpat Superior Single 77EUR">Dorpat Superior Single 77EUR</option>
                <option value="Dorpat Superior twin 93EUR">Dorpat Superior twin 93EUR</option>
             </select> </td>
        </tr>
        <tr>
 <tr>
            <td valign="top"><label for="hotel_BLA"><font face="verdana" size="2">Hotel BLA</font></label> <select
            name="hotel_BLA" size="1">
                <option value="bla1">bla1</option>
                <option value="bla2">bla2</option>
             </select> </td>
        </tr>
        <tr>
            <td colspan="2"...